https://www.cnet.com/news/apple-pulls-watch-os-5-1-update-after-users-report-problems/

News of the problems with the software update was previously reported by 9to5mac. 

The big improvement in Watch OS 5.1 was an enhancement to its fall detection system. Once 5.1 was successfully installed, a detected fall would be followed by a recorded message to emergency services, offering location information (latitude and longitude). Previously, that location information was sent to a key emergency contact instead.